Added randomRange, improve AA

src/Maths.hs

@@ -4,6 +4,7 @@ module Maths
     unitVector,
     randV3,
     rand,
+    randRange,
     reflect,
     refract,
     reflectance,
@@ -19,6 +20,9 @@ import System.Random
 rand :: (RandomGen g) => Rand g Double
 rand = getRandomR (-1.0, 1.0 :: Double)
 
+randRange :: (RandomGen g) => Double -> Double -> Rand g Double
+randRange a b = getRandomR (a, b :: Double)
+
 randV3 :: (RandomGen g) => Rand g (V3 Double)
 randV3 = do
   x <- rand

src/Ray.hs

@@ -25,8 +25,8 @@ calculateRayNormal r t = unitVector (rayAt r t ^-^ V3 0.0 0.0 1.0)
 
 buildRayAA :: (RandomGen g) => Double -> Double -> Double -> Double -> Camera -> Rand g Ray
 buildRayAA u v w h camera = do
-  ur <- rand
+  ur <- randRange 0 1
-  vr <- rand
+  vr <- randRange 0 1
   return $ buildRay ((u + ur) / w) ((v + vr) / h) camera
 
 buildRay :: Double -> Double -> Camera -> Ray